9.3.2 TUNEL Methods
TUNEL methods are useful for defining distribution of cells with DNA
breaks to assist in ultrastructural analysis. This method has also been used
on material destined for electron microscope and provides perhaps the best
and most direct way to correlate DNA cleavage with observed morphological
changes.
25
The objection to a pure criterion of TUNEL staining for apoptosis
is that generalized endonuclease digestion of DNA may be observed
in necrotic cells.
11,12,26
Internucleosomal cleavage typical of programmed cell
Downloaded by death should result in defined fragments identifiable by ladder pattern on
electrophoresis.
11,12